1. Field of the Invention
The present invention generally relates to engineering and management systems for the design of communications networks and, more particularly, to a method for optimizing the types of, locations for, and configurations of communication hardware components in communication systems in any environment in the world (e.g. buildings, campuses, floors within a building, within cities, or in an outdoor setting, etc.) using a three-dimensional (3-D) representation of the environment and utilizing selected areas within the environment referenced herein as to ensure critical communication system performance is maintained.
2. Background Description
The importance of communication network performance has quickly become an important design issue for engineers who must design and deploy communication system equipment, telephone systems, cellular telephone systems, paging systems, or new wireless communication systems and technologies such as personal communication networks or wireless local area networks. For wireless communication systems, designers are frequently requested to determine if a radio transceiver location, or base station cell site can provide reliable service throughout an entire city, an office, building, arena or campus. A common problem for wireless systems is inadequate coverage, or a “dead zone,” in a specific location, such as a conference room, subway tunnel, or alleyway. It is now understood that an indoor wireless PBX (private branch exchange) system or wireless local area network (WLAN) can be rendered useless by interference from nearby, similar systems. The costs of in-building and microcell devices which provide wireless coverage within a 2 kilometer radius are diminishing, and the workload for RF engineers and technicians to install these on-premises systems is increasing sharply. Rapid engineering design and deployment methods for wireless systems are vital for cost-efficient build-out. In similar fashion, the configuration of various components comprising a wired communication network can dramatically impact the overall performance of the remainder of the communication system. The physical location of and configuration of a computer network router relative to other components in a computer network is important to the optimal performance of the network as a whole.
For wireless communication systems, analyzing radio signal coverage penetration and interference is of critical importance for a number of reasons. A design engineer must determine if an existing outdoor large-scale wireless system, or macrocell, will provide sufficient coverage throughout a building, or group of buildings (i.e., a campus). Alternatively, wireless engineers must determine whether local area coverage will be adequately supplemented by other existing macrocells, or whether indoor wireless transceivers, or picocells, must be added. The placement of these cells is critical from both a cost and performance standpoint. If an indoor wireless system is being planned that interferes with signals from an outdoor macrocell, the design engineer must predict how much interference can be expected and where it will manifest itself within the building, or group of buildings. Also, providing a wireless system that minimizes equipment infrastructure cost as well as installation cost is of significant economic importance. As in-building and microcell wireless systems proliferate, these issues must be resolved quickly, easily, and inexpensively, in a systematic and repeatable manner.
Several patents related to, and which allow, the present invention are listed below:    U.S. Pat. No. 5,491,644 entitled “Cell Engineering Tool and Methods” filed by L. W. Pickerting et al;    U.S. Pat. No. 5,561,841 entitled “Method and Apparatus for Planning a Cellular Radio Network by Creating a Model on a Digital Map Adding Properties and Optimizing Parameters, Based on Statistical Simulation Results” filed by O. Markus;    U.S. Pat. No. 5,794,128 entitled “Apparatus and Processes for Realistic Simulation of Wireless Information Transport Systems” filed by K. H. Brockel et al;    U.S. Pat. No. 5,949,988 entitled “Prediction System for RF Power Distribution” filed by F. Feisullin et al;    U.S. Pat. No. 5,987,328 entitled “Method and Device for Placement of Transmitters in Wireless Networks” filed by A. Ephremides and D. Stamatelos;    U.S. Pat. No. 5,598,532 entitled “Method and Apparatus for Optimizing Computer Networks” filed by M. Liron; and    U.S. Pat. No. 5,953,669 entitled “Method and Apparatus for Predicting Signal Characteristics in a Wireless Communication System” filed by G. Stratis et al.
There are many computer aided design (CAD) products on the market that can be used to design a model of the environment for use in wireless communication system design. SitePlanner from Wireless Valley Communications, Inc., WiSE from Lucent Technology, Inc., SignalPro from EDX, PLAnet by Mobile Systems International, Inc., Wizard by TEC Cellular, and WinProp from AWE are examples of such wireless CAD products. In practice, however, information regarding a pre-existing building or campus is available only in paper format and a database of parameters defining the environment in a manner suitable for radio wave propagation analysis does not readily exist. It has been difficult, if not generally impossible, to gather this disparate information and manipulate the data for the purposes of planning and implementing indoor and outdoor RF wireless communication systems, and each new environment requires tedious manual data formatting in order to run with computer generated wireless prediction models. Recent research efforts by AT&T Laboratories, Brooklyn Polytechnic, Pennsylvania State University, Virginia Tech, and other leading research centers are described in papers and technical reports, including:    S. Kim, B. J. Guarino, Jr., T. M. Willis III, V. Erceg, S. J. Fortune, R. A. Valenzuela, L. W. Thomas, J. Ling, and J. D. Moore, “Radio Propagation Measurements and Prediction Using Three-dimensional Ray Tracing in Urban Environments at 908 MHZ and 1.9 GHz,” IEEE Transactions on Vehicular Technology, Vol. 48, No. 3, May 1999;    L. Piazzi and H. L. Bertoni, “Achievable Accuracy of Site-Specific Path-Loss Predictions in Residential Environments,” IEEE Transactions on Vehicular Technology, Vol. 48, No. 3, May 1999;    G. Durgin, T. S. Rappaport, and H. Xu, “Measurements and Models for Radio Path Loss and Penetration Loss In and Around Homes and Trees at 5.85 Ghz,” IEEE Transactions on Communications, Vol. 46, No. 11, November 1998;    T. S. Rappaport, M. P. Koushik, J. C. Liberti, C. Pendyala, and T. P. Subramanian, Radio Propagation Prediction Techniques and Computer-Aided Channel Modeling for Embedded Wireless Microsystems, ARPA Annual Report, MPRG Technical Report MPRG-TR-94-12, Virginia Tech, Blacksburg, Va., July 1995;    H. D. Sherali, C. M. Pendyala, and T. S. Rappaport, “Optimal Location of Transmitters for Micro-Cellular Radio Communication System Design,” IEEE Journal on Selected Areas in Communications, Vol. 14, No. 4, May 1996;    T. S. Rappaport, M. P. Koushik, C. Carter, and M. Ahmed, Radio Propagation Prediction Techniques and Computer-Aided Channel Modeling for Embedded Wireless Microsystems, MPRG Technical Report MPRG-TR-95-08, Virginia Tech, Blacksburg, Va., July 1995;    M. Ahmed, K. Blankenship, C. Carter, P. Koushik, W. Newhall, R. Skidmore, N. Zhang and T. S. Rappaport, Use of Topographic Maps with Building Information to Determine Communication component Placement for Radio Detection and Tracking in Urban Environments, MPRG Technical Report MPRG-TR-95-19, Virginia Tech, Blacksburg, Va., November 1995;    R. R. Skidmore and T. S. Rappaport, A Comprehensive In-Building and Microcellular Wireless Communications System Design Tool, master's thesis, Virginit Tech, Dept. Electrical and Computer Engineering, Blacksburg, Va., 1997;    T. S. Rappaport, M. P. Koushik, M. Ahmed, C. Carter, B. Newhall, and N. Zhang, Use of Topographic Maps with Building Information to Determine Communication component Placements and GPS Satellite Coverage for Radio Detection and Tracking in Urban Environments, MPRG Technical Report MPRG-TR-95-14, Virginia Tech, Blacksburg, Va., Sep. 15, 1995;    S. Sandhu, P. Koushik, and T. S. Rappaport, Predicted Path Loss for Rosslyn, Va., MPRG Technical Report MPRG-TR-94-20, Virginia Tech, Blacksburg, Va., Dec. 9, 1994;    S. Sandhu, P. Koushik, and T. S. Rappaport, Predicted Path Loss for Rosslyn, Va., Second set of predictions for ORD Project on Site Specific Propagation Prediction, MPRG Technical Report MPRG-TR-95-03, Virginia Tech, Blacksburg, Va., Mar. 5, 1995;    W. Rios, A. Tan, and T. S. Rappaport, SitePlanner Outdoor Simulation Measurements at 1.8 GHz, MPRG Technical Report, Virginia Tech, Blacksburg, Va., Dec. 18, 1998;    P. M. Koushik, T. S. Rappaport, M. Ahmed, and N. Zhang, “SISP—A Software Tool for Propagation Prediction,” Advisory Group for Aerospace Research and Development, Conference Proceedings 574, Athens, Greece, 1995;    T. S. Rappaport and S. Sandhu, “Radio-Wave Propagation for Emerging Wireless Personal Communication Systems,”, IEEE Antennas and Propagation Magazine, Vol. 36, No. 5, October 1994;    N. S. Adawi, H. L. Bertoni, J. R. Child, W. A. Daniel, J. E. Dettra, R. P. Eckert, E. H. Flath, R. T. Forrest, W. C. Y. Lee, S. R. McConoughey, J. P. Murray, H. Sachs, G. L. Schrenk, N. H. Shepherd, and F. D. Shipley, “Coverage Prediction for Mobile Radio Systems Operating in the 800/900 MHz Frequency Range,” IEEE Transactions on Vehicular Technology, Vol. 37, No. 1, February 1988;    M. A. Panjwani and A. L. Abbott, An Interactive Site Modeling Tool for Estimating Coverage Regions for Wireless Communication Systems in Multifloored Indoor Environments, master's thesis, Virginia Tech, Dept. Electrical and Computer Engineering, 1995;    S. Y. Seidel and T. S. Rappaport, “Site-Specific Propagation Prediction for Wireless In-Building Personal Communication System Design,” IEEE Transactions on Vehicular Technology, Vol. 43, No. 4, November 1994; K. L. Blackard, T. S. Rappaport, and C. W. Bostian, “Measurements and Models of Radio Frequency Impulsive Noise for Indoor Wireless Communications,” IEEE Journal on Selected Areas in Communications, Vol. 11, No. 7, September 1993;    R. A. Brickhouse and T. S. Rappaport, “Urban In-Building Cellular Frequency Reuse,” IEEE Globecom, London, England, 1996;    S. J. Fortune et al, “WISE Design of Indoor Wireless Systems: Practical Computation and Optimization,” IEEE Computational Science and Engineering, 1995;    T. S. Rappaport et al, Use of Topographic Maps with Building Information to Determine Antenna Placement for Radio Detection and Tracking in Urban Environments, MPRG Technical Report MPRG-TR-96-06, Virginia Tech, Blacksburg, Va., 1995;    K. Feher, Wireless Digital Communications: Modulation and Spread Spectrum Applications, Prentice Hall, Upper Saddle River, N.J., 1995; T. S. Rappaport, Wireless Communications Principles and Practices, Prentice Hall, Upper Saddle River, N.J., 1996;    R. Hoppe, P. Wertz, G. Wolfle, and F. M. Landstorfer, “Fast and Enhanced Ray Optical Propagation Modeling for Radio Network Planning in Urban and Indoor Scenarios,” Virginia Tech Symposium on Wireless Personal Communications, Vol. 10, June 2000;    Xylomenos, G., Polyzos., G. C., “TCP and UDP Performance over a Wireless LAN,” Proceedings of IEEE INFOCOM, 1999;    Maeda, Y., Takaya, K., and Kuwabara, N., “Experimental Investigation of Propagation Characteristics of 2.4 GHz ISM-Band Wireless LAN in Various Indoor Environments,” IEICE Transactions in Communications, Vol. E82-B, No. 10 Oct. 1999;    Duchamp, D., and Reynolds, N. F., “Measured Performance of a Wireless LAN,” Proceedings of the 17th Conference on Local Computer Networks, 1992.    Bing, B. “Measured Performance of the IEEE 802.11 Wireless LAN,” Local Computer Networks, 1999;    Hope, M. and Linge, N., “Determining the Propagation Range of IEEE 802.11 Radio LAN's for Outdoor Applications,” Local Computer Networks, 1999;    Xylomenos, G. and Polyzos, G. C., “Internet Protocol Performance over Networks with Wireless Links,” IEEE Network, July/August;    J. Feigin and K. Pahlavan, “Measurement of Characteristics of Voice over IP in a Wireless LAN Environment,” IEEE International Workshop on Mobile Multimedia Communications, 1999, pp. 236–240;    B. Riggs, “Speed Based on Location,” Information Week, No. 726, March 1999;    J. Kobielus, G. Somerville, and T. Baylor, “Optimizing In-Building Coverage,” Wireless Review, Vol. 15, No. 5, pp. 24–30, March 1998;    A. W. Y. Au and V. C. M. Leung, “Modeling and Analysis of Spread Spectrum Signaling with Multiple Receivers for Distributed Wireless In-Building Networks,” IEEE Pacific Rim Conference on Communications, Computers and Signal Processing 1993, Vol. 2, pp. 694–697;    K. L. Blackard, T. S. Rappaport, and C. W. Bostian, “Radio Frequency Noise Measurements and Models for Indoor Wireless Communications at 918 MHz, 2.44 GHz, and 4.0 GHz,” ICC 1991, vol. 1, pp. 28–32, 1991; R. R. Skidmore, T. S. Rappaport, and A. L. Abbott, “Interactive Coverage Region and System Design Simulation for Wireless Communication Systems in Multifloored Indoor Environments: SMT Plus,” IEEE International Conference on Universal Personal Communications, Vol. 2, pp. 646–650, 1996; and    M. A. Panjwani, A. L. Abbott, and T. S. Rappaport, “Interactive Computation of Coverage Regions for Wireless Communication in Multifloored Indoor Environments,” IEEE Journal on Selected Areas in Communications, Vol. 14, No. 3, pp. 420–430, 1996.
These papers and technical reports are illustrative of the state of the art in communication system modeling and show the difficulty in obtaining databases for city environments, such as Rosslyn, Virginia, and are hereby included by reference. While the above papers describe a research comparison of measured vs. predicted signal coverage, the works do not demonstrate a systematic, repeatable and fast methodology for creating an environmental database, nor do they report a method for visualizing and placing various environmental objects that are required to model the performance of a communication system in that environment. Further, none of the cited works provide for an automated method for optimally designing communication systems in three-dimensional space.
While there are methods available for designing communication networks that provide adequate system performance, these known methods involve costly and time consuming predictions of communication system performance that, while beneficial to a designer, require too much time to be applied in a real time manner.